Method of distilling oils



Dec. 29, 1931. P. c. KEITH, 'JR

METHOD OF DISTILLING OILS Filed July lO, 1928 &

vwemtoz Patented Dec. 29, 1931 UNITED STATES PATENT oFlElcfE/ PERCY C. KEITH, JR., OF ,BERNARDSVILLE NEW JERSEY, ASSAIGNOR TO THE M'. W. KELLOGG- COMPANY, OF NEW YORK, N. Y., A CORPORATIONOF DELAWARE METHOD OF DISTILLING OILS Application led July 10,

3 ing description read in conjunction with the drawings in which Fig. 1 is a side elevation, principally in section, of apparatus in which my method may-l be carried into effect, and

Fig. 2 is a vertical section in detail of part of Fig. 1. l

`Referring specilically to Fig. 1, the inlet pipe 1, controlled by the valve 2, isadapted to supply crude oil to a tubular heater 3 which is shown diagrammatically insection. This heater consists of a series of tubes joined end to end by crossover connections to form a continuous circuit and\will be hereinafter referred to as a pipe still.

The pipe still 3 is surroundedJby any suitable refractory setting 4, heated through the port 5 by the burner 6. The pipe still discharges through the outlet 3 andthe distributo'r 4 into a separating drum 5. The pipe 3 and the separating drum 5 are covered by insulation 3a and 6 respectively to, mini-yv `Inize heat loss therefrom. The drum 5 carries transverse partitions 7 and 8 located respectively below and above the distributor 4.

These transverse partitions are equipped with conventional vapor distributors such as bell caps and overflow pipes, not shown. The base of the drum carries an overiiow pipe 9 which projects upwardly therein to considcent to` the lower portion .thereof and dis-l fchar'geinto the pump 12 which is adapted to force liquid through the pipe 13 and therel5 by into the bank of tubes 14 in the refractory setting 4. The pipe 15 is connected to the outlet end of the bank of tubes 14 and is controlled bythe valve 16. The arrangement is such that liquid may be continuously withi0- drawn from the base of drum 5, heated in a erable height to permit the accumulation of 1928. Serial No. 291,608.

confined stream returned to the body of liquid maintained in the lower part of the drum.

The pipes 11, 13 and 15 are covered by thermal insulation lla, 13a and 15a respectively. Steam may be admitted to the drum 5 by mea-ns of'a pipepl? controlled by the valve 18 discharging into the distributor 19.

A vapor outlet pipe 2O leads from the upper part of the drum into the lower part of the rectifying column 21. The column 21 is preferably surrounded by thermal insulation, not shown. The pipe 20 is covered by insulation 20a. .The column 2l is equipped with a number of horizontal artitions 22 which carry vapor distributors, ell caps and overflow pipes, net shown. The equipment is such that rectifying conditions maybe maintained in the column and provision is made for withdrawing a number of intermediate cuts from the column by means of pots 23, 24, 25, 26 and 27. These pots are provided with the pipes 28, 29, 30, 31- and 32 for the introduction of steam in the same for stripping and the pipes 33, 34, 35, 36 and 37 for carrying away the distillates to be withdrawn from the column. There are two condensing coils 38 and 39 in the upper part of the column. 38 may be supplied with cooling water through the'inlqt pipe 40 and coil 39 with oil through the pipe 41. is is preferably the feed oil for the apparatus, which is thereby preheated and discharged into the pipe 1 whereby it is conducted into the pipe still 3. Any bottoms accumulating in the base of the rectifying column 21 may be continuously .or periodically withdrawn through the ma be supplied pipe 42 controlledby the valve 4 3 to a suity conducted away through the pipe 44. The

foregoing apparatus isY adapted to be operated runder vacuum and is preferably operated in this-manner. This vacuum is preferably maintainedv by the operation vof a jet ejector or booster 45. This booster is connect.- ed withthe pipe 46 which discharges into the vbarometric condenser 47. Conden'sing water for the barometric condenser is introduced through pipe 48 controlled by valve 49. The booster 45 is adapted to take gases at very low pressures, say from a few millimeters up to fifty-and by the action of jets of superheated steam of high velocity tobuild troduced through the pipe 45azcontrolled by the valve 45?).

Referrin specifically to Fig. 2, the pot 25 is typical o the construction of the members 23, 24, 25, 26 and 27. It consists of an enclosed tank located on one of the horizontal partitions 22 of the tower. It carries a single tray 50 provided with bell caps or'equivalent vapor distributors 51 and an overiiow pipe 52. Oil is passed on to the partition 51 by means of the pipe 53 controlled by the valve 54 which drains oil from the horizontal partition immediately above. Steam is introduced through the pipe 30 controlled by the valve 3l, and discharged into the potv 25 through the distributor 55. The steam may be controlled by manipulating valve 31a so as to strip the light ends from any oil discharging-through the pipe 53 on to the plate 51 and the stripped oil flows off continuously through the pipe 35. vThe steam and oil vapors which it carries pass upwardly through the pipe 56 to be discharge above the next higher horizontal partition.

, 41, preheater 39 and pipe 1.

The method of operation of the apparatus is as follows:

A crude petroleum is passed into the pipe The phrase crude petroleum or crude oil as employed herein denotes either a crude petroleum in its native condition as recovered from the well or a petroleum which has been topped or otherwise fractionated to divest it of lighter constituents. A preferred form of crude oil for my purpose'consists in a native crude petroleum from which the gasoline, kerosene and gas oil have been removed leaving a re.- siduum principally of lubricating components. The crude oil is heated in the pipe still 3 by the burner 6 to a temperature sufficient to effect partial vap'orization, preferably toa temperature between 600 and 800 F.; this material discharges throu h the distributor 4 into4 the drum 5. eparation takes place in this drum, the vaporized constituents pass'upwardly and by means of the vapor outlet 20 are diverted into the recti` fyingl column 21.

Y tions pass downwardly over the partition 7 i and are stripped by the introduction of steam,

preferably super-heated, through the distributor 19. A liquid residuum accumulates in -the column 21 are continuously rectified) -under conditions of4 partial or substantially The unvaporized por complete condensation andl a series of intermediate cuts are taken off through the pipes 33, 34, 35, 36 and 37.

My preferred method of operating the column, consists in controlling the cooling medium supplied by coils 38 and 39, so as to produce substantially complete condensation of hydrocarbon vapors inthe upper part of the column while permitting substantially all the steam to lpass overhead and out through the pipe 44. The absolute pressure in the upper part of the column is maintained at relatively low, say from a few millimeters up to about fifty, and this pressure is built up by means of the jet ejector 45 at the ejector outlet to a pressure of say to 150 millimeters of mercury which may be conveniently taken care of by the operation of the barometric condenser 47.

l have found that a particularly eiicient and economical method for operating this distillation consists in continuously abstracting a small quantity of the liquid residuum in the base of the drum 5 and pumping this through the heating coil 14 by which it is elevated in temperature so that the entire body of the residuum in the base of the drum 5 may be held at an optimum temperature regardless of the inevitable thermal losses.

This is of value inpermitting exact control of the total amount of the crude oil which is to be taken overhead and through the pipe 20 as vapors and resolved into lubricating distillates. It is further of value in permitting the exact control of the consistency of I maintain the residuum in the base .of the drum at a temperature of 600 to 800o E. or alternately at a temperature at which hydrocarbon vapors are vigorously and actively developed and thefsaid mixed're'siduum is` evolved therefrom. When operating under relatively/lowpressures, say less than two hundred millimeters of mercury absolute, and a temperature above 700 F. l find that the tar constituents of the residuum tend to rearrange themselves and contribute mate rially to the total quantity of lubricating oil whichmay be recovered from any particular stock.

The petroleum vapors produced in this way pass upwardly and commingle with those produced by partial vaporization of the original stock and are simultaneously rectified in the column 21, to produce the individual lubricating cuts hereinabove referred to.

The foregoing description of my method is for purposes of illustration and not by way-of limitation. It'is my intention that the invention belimited only by the appended claims or. their equivalent in which I have endeavored to claim broadlyE all inherent novelty.

I claim:

1. The method of distilling hydrocarbon loils which comprises passing crude petroleum v 011 in a confined stream through a zone of heat, heatin it in said confined stream to partly vaporize the said'crude petroleum, discharging the partly vaporized crude petro-` leum into a separatin zone maintained under vacuum, separating .1t therein to produce a separated vapor and a liquid residuum, maintaining a body of the said separated residuum, continuously abstractin liquid from the said body, conducting the a stracted liquid in a confined stream through a zone of heat, thereby heating the same, and returning all the heated material to said maintained body.

2. The method of distilling hydrocarbon oils which comprises conducting crude petroleum oil in a confined stream through a zone of heat, heating it therein to a temperature suiiicient to partly vaporize the same, discharging the heated oil into a separating zone maintained underl vacuum, separating it therein to produce a vapor and an unvaporized liquid residuum, maintaining a body of unvaporized liquid residuum, Icontinuously abstracting li uid from the said body, conducting the a tracted liquid in a confined stream thru a zone of heat, thereby heating the liquid abstracted, and returning all the heated material to the said maintained body, the

amount'of heat thereby introduced being suiiicent to maintain the said body at a temperature of 600o to 800 F.

3. The method of distilling hydrocarbon oils which comprises conducting crude petroleum oil in a confined stream through a zone of heat, heating it therein to a temperature suiiicient to partly vvaporize the same, dis'- charging the heated petroleum oil into a separating zone .maintained under vacuum, separating it therein to produce a petroleum vapor and a liquid residuum, maintaining a is free communication with the said separatni zone.

6. ethod according to claim 3 in which the sald maintained body of liquid residuum 1s 1n free communication with the said separating zone.

7 The method of forming lubricating dis-I tillatev from crude petroleum oil which comprises conductin crude petroleum oil in a confined stream t rough a zone of heat, heating it therein to a temperature suicient to partly vaporize the same, discharging the heated crude petroleum into a separating zone maintained under vacuum, separating it therein to produce a petroleum vapor and a hquid residuum, maintaining a body of liquid residuum in free communication with said separating zone, continuously abstracting part of the said residuum, conducting the PERCY C. KEITH, JR.

body of said liquid residuum, continuously abstracting liquid from the said maintained body, conducting the abstracted liquid in a ooniined stream through a zone of heat, heating it in said zone of heat and returning all the heated material to said maintained body, the amount of heat thereby introduced being suicient to maintain the said body at a temperature at which vapor isactively and con tinuously evolved therefrom.

4. Method according to claim 1 in which the said maintained body of liquid residuum is in free communication with the said separating'zone.

5. Method according to claim 2 in which the said maintained body of' liquid residuum 

